The Effect of Different Prosthetic Components
The same issue of JRRD that contained Hansen's paper also included an excellent literature review conducted by a group of rehabilitation professionals in the Netherlands. [van der Linde H, Hofstad HJ, Guerts ACH, Postema K, Geertzen JHB, van Limbeek J. A systematic literature review of the effect of different prosthetic components on human functioning with a lower-limb prosthesis . JRRD 2004; 41(4): 555-570.] This group reviewed 356 potential relevant studies that might shed light on the objective basis for the prescription of specific prosthetic components. Forty had sufficient control for selection and measurement bias to warrant complete review and synthesis, with 4 considered "A level" that included a blinded outcome assessment. No randomized controlled studies [RCTs] were identified among the 350+ English, German, and Dutch language studies reviewed.
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I had read almost all of the cited studies as they were published, incorporating their findings into my clinical thinking over the years, but had not always reread them a decade or more later in light of subsequent research. Van der Linde et al did an excellent job of summarizing and presenting the key findings from these publications in tabular form.
Since these forty-some articles are the key literature about a major aspect of our clinical practices, I urge all readers to take the time to really study this paper. In fact, anyone interested in the science of prosthetic practice would be well advised to go back and reread all of the original articles, to fully appreciate the nuances of this body of evidence.
Table Three, "Major clinical findings of reviewed studies on prosthetic feet" will be of great interest to CPOs. Not only did this group accurately summarize the conclusions from these studies, but they also provided good clinical interpretations of the significance of the results, and carefully noted contradictory results from different researchers. Clinicians who study this information will have an excellent understanding of how much, as well as how little, objective information we currently have regarding prosthetic ankle-foot function.
Table Four, " Major clinical findings of reviewed studies on prosthetic knee, prosthetic socket, and prosthetic mass " will also be of interest, but the limited number of good studies permits only a few tentative conclusions to be drawn. One key finding was that more advanced prosthetic knee controls in swing phase clearly results in a faster and more symmetrical amputee gait. It is equally clear those clinically practical changes in the mass and mass distribution of prostheses offer little significant benefit in the amputee's gait pattern or in energy consumption.
These authors conclude that, given the present gaps in scientific knowledge about the functioning of prosthetic components, "we must still rely primarily on clinical consensus among experts" in determining prescription guidelines. They also recommend that future studies should categorize components according to the activity level of the amputee and the intended use of the prosthesis, noting that the most solid base for prescription will be the future integration of objective knowledge from research with expert clinical opinion and consumer wishes.
In April of this year, the American Academy of Orthotists & Prosthetists will be convening a multidisciplinary blue ribbon panel to review the best available evidence, including this key article, to establish the State of the Science regarding Prosthetic Ankle-Foot Mechanisms. The results from those deliberations will be published as a Supplement to the JPO later in the year.
Interested readers can find the full text and all tables from this article online at www.vard.org/jour/04/41/4/van%20der%20linde.html .
